Thanks for the many replies so far. So today after I got home from work I
tried just running radio A @ about 1w on 7.000MHZ and saw S9 on 20m and s1 on
10m.
No change switching stub in or out, so I took Jim’s(K9YC) suggestion and moved
the stub farther away from the transceiver. I made up 3 random length patch cables
and so have the stub roughly either:
10-12’, 15’-17, 20’-22, 25’-27 away from the transmitter (Radio A). (rough guesstimates) ( a
1/4wl, accounting for VF would be in the 23’-27’ range)
No perceptible change whatsoever at any point in the line no matter where I put
the stub. Just the slightest SWR change when I put it in line. Almost cannot
detect it.
I am going nuts.
It’s either something in the shack or something outside rectifying (I guess?)
but these are pretty low power levels. (usually 100w, but also at 1w !)
Radio A (transmitter in the scenario) is hooked to an amp (not turned on in close to a
year), an antenna switch, a tuner/wattmeter (used on straightthrough function only,
just for it’s wattmeter/SWR function.)
Radio B (receiver in this scenario) is hooked to its own power supply and coax straight outside to a
multiband dipole some 100’ from the Radio’s A’s various antennas. No SWR
meters, switches or anything.
They share a 4” hole in the wall in the garage where they exit to the outside, where
the RG8 or LMR400 coax;’s could be close to one another.
They share 120VAC in the shack (but different power supplies)
I have two additional (perhaps important?) questions. Should any of these harmonics between
any bands sound pure and “clean”, like a real CW signal? Mine all sound
low/muffly, wide, growly, like they have buzzing/humming AC riding on top of them.
Additionally, the AA-230pro’s manual says to make the 1/4WL stub with the end
of the coax OPEN. . . . .but then for the purposes of these tests, I am using the
stubs shorted.
Maybe I have a ground loop somewhere and there is feedback or an isolation problem on
the shacks’s 120VAC line?
Mike
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